Adjustable screen frame holder

ABSTRACT

What follows is a description of an exemplary silk screen printing assembly for printing on flat as well as cylindrical objects. The assembly includes a support frame within which a screen is fastened, a support structure for mounting the support frame and a squeegee assembly mounted on the support structure. The support structure includes a rigid frame member and parallel spaced telescopic elements which are supported for movement relative to the rigid frame member. The elements of the assembly described are operatively associated so that the screen can be moved relative to the squeegee or the squeegee can be moved relative to the screen in order to apply a stencil to a surface positioned beneath the assembly.

[451 Jan. 14, 1975 United States Patent Dargols ADJUSTABLE SCREEN FRAME HOLDER FOREIGN PATENTS OR APPLICATIONS 918,278 2/1963 Great Britain...................... 101/124 [76] Inventor: Bernard Dargols, 75 Rue des Montalaus, Colombes, France Aug. 30, 1973 Primary Examiner-Robert E. Bagwill Assistant Examiner-R. E. Suter [22] Filed:

211 Appl. No.: 393,032

Attorney, Agent, or Firm-Edwin E. Greigg Related US. Application Data [63] Continuation of Ser. No. 102,868, Dec. 30, 1970,

abandoned.

[30] Foreign Application Priority Data Dec. 30, 1969 France.................,............ 69.45481 frame within which a screen is fastened, a support structure for mounting the support frame and a squee- [52] US. l01/l27.l, l0l/123, 101/124 gee assembly mounted on the support Structure The [51] Int. Cl. B4lf 15/36, B4lf 15/42 support structure includes a rigid frame member and [58] Field of Search l0l/127.1, 123, 124, 114,

parallel spaced telescopic elements which are supported for movement relative to the rigid frame member. The elements of the assembly described are oper' [56] References Cited UNITED STATES PATENTS atively associated so that the screen can be moved relative to the squeegee or the squeegee can be moved relative to the screen in order to apply a stencil to a surface positioned beneath the assembly.

10] 23 3 Claims, 4 Drawing Figures 952,589 3/1910 Tanner............................. 1,586,088 5/1926 Jellow 2,087,082 7/1937 Brasseur 3,486,441 12/1969 Hillman I 1- ADJUSTABLE SCREEN FRAME HOLDER This is a Continuation of application Ser. No. 102,868, filed Dec. 30, I970, now abandoned.

INTRODUCTION The present invention relates to improvements in the printing head of a silk screen device for printing of flat as well as cylindrical objects.

BACKGROUND OF THE INVENTION In silk screen printing processes, a screen is used which consists of a cloth having a photosensitive layer. The cloth is held by a frame having suitable dimensions. The photosensitive layer material obstructs those meshes of the screen which are to constitute the nonprinting areas. Further, a scraper is, during the printing, moved in relation to the screen and rubbed thereagainst so that a liquid ink is thereby urged to penetrate the non-obstructed meshes of the screen.

Generally, to obtain a printing on a flat surface, the screen is retained in a fixed manner above and very close to the surface to be printed. The scraper is then reciprocated longitudinally. When the scraper is moved in one of the directions, it is swingably raised in order not to touch the screen, and when moving in the other direction, it is pressed against the screen to such an extent that the screen comes into intimate contact with the surface to be printed. The screen is resiliently and continuously deformed along the transverse line of contact between the scraper and the screen as the scraper travels over the screen and the surface to be printed.

When a cylindrical object is to be printed, the scraper is retained in a fixed position and the screen ismoved. The'cylindrical object is retained by small rollers in such a position that it can be rotated about its own axis. The doctor blade, i.e., the active edge, of the scraper is retained in such a position that it is continuously pressed against the line which is formed where the movable screen surface and the movable surface of the object to be printed come in contact with each other. The screen is moved and makes-the object move while overcoming the pressing force exerted by the scraper.

Some known silk screen devices can be used for printing flat as well as cylindrical objects. They are provided with a printing head which forms the upper portion of the silk screen device. The printing head comprises a fixed frame, in which a screen holder frame slides longitudinally. A scraper holder carriage also slides longitudinally and in such a manner that it may pass in front of the forward face of the structure. The support of the cylindrical objects to be printed is retained disposed in alignment with this disengaged position of the scraper. To produce prints on a flat article, the latter is placed on a flat support, which is slidably mounted in the silk screen device.

The above-described silk screen devices have certain shortcomings, such as complicated design, inflexibility as to the dimensions of the printings which can be produced, cumbersomeness, inconvenient handling and relatively high costs.

OBJECT AND SUMMARY OF THE INVENTION The object of the present invention is to eliminate the above-noted shortcomings of silk screen devices. Briefly stated, according to the invention, the printing head of the screen device comprises two parallel rails or U-beams rigidly connected by at least one cross bar and a telescopic slide which is telescopic with respect to the U-beams. The telescopic slide includes external or outer members and internal or inner members. In each of the U-beams the outer member ofa telescopic slide is slidably mounted as in the prior art, while the free ends of the inner members of the slide are connected by means of a frontal cross bar, the length of which preferably is substantially the same as the length of the U-beams. The printing head also comprises a scraper rotatably mounted about an axis supported by a carriage which is rigidly mounted to two slide members each of which is slidable on the surfaces of a respective one of the inner members of the telescopic slide. The carriage can be connected to the rear cross bar of the U-beams by means of a telescopic arm. The arm can be subjected to resilient means and urge the carriage in a longitudinal direction when the printing head is being deployed. Finally, it should be noted that the printing head can assume an undeployed (fully closed) position, a maximum deployed (fully opened) position or any deployed position therebetween. For each of these positions a screen holder frame is fixedly positioned to the bottom portion of the printing head.

According to a preferred embodiment of this invention the length of the telescopic arm which connects the rear cross bar and the scraper holder carriage, can be varied.

The length of each of the transverse members of the printing head, i.e., the frontal cross head, the rear cross bar of the rails and the scraper holder carriage can be varied to permit the use of screen holder frames of different widths.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be more fully understood embodiments in accordance therewith will now be descriped by way of examples with reference to the accompanying drawings, in which:

' FIG. 1 is a perspective view of an undeployed printing head of the invention;

FIG. 2 is a perspective view of the same printing head in a deployed position for flat surface printing;

FIG. 3 is a perspective view of a printing head provided with a holder for a cylindrical object to be printed; and

FIG. 4 is a perspective view of a deployed printing head according to FIG. 2, including means for width adjustment.

DESCRIPTION OF THE EMBODIMENTS In FIGS. 1-3, a printing head for silk screening is shown which comprises a support frame 1 on which a screen 2 is stretched, a support structure to which the frame 1 is mounted, and a squeegee type scraper 3 which is pivotally mounted on an axle 4. The support structure includes essentially two parallel U-beams 5a, 5b which are rigidly connected by a rear cross bar 6. The U-beam 5a, 5b and'the cross bar 6 form a rigid frame member. In each of the U-beams external members 7a, 7b glide. Only member 7a is shown although due to the symmetrical aspect of the support structure, it should be clear that member 7b is similarly disposed. The external members 7a, 7b form part of a telescopic slide or movable portion. The telescopic slide or movable portion also includes internal members 8a, 8b. The

be mounted to the rear cross bar 6 by a clevis joint 17,

which in turn is mounted to the cross bar 6 in a conventional manner (FIG. 3). When the arm 11 is put in place as shown, it connects the carriage 10 to the rear cross bar 6. A helical spring (not shown) within the arm 11 tends to keep, it extended by pushing its inner member up to a stop; the stop being adjustable by means of a threaded nut 12.

The printing head can be used in conjunction with a known object holder 23, which is designed to receive a cylindrical object on freely rotating rollers whose height and separation are adjustable by means of knurled knobs such as 28a, 28b which are mounted on their axes and which are intended to fix the latter in predetermined relative positions.

The function is believed to be clear. To make a flat printing, the support structure is put either into a retracted position (FIG. 1) or into an extended position (FIG. 2) or into some intermediate position such that its length corresponds to that of the screen holding frame 1 required to achieve the desired printing.

Once the frame 1 is affixed to the support structure, which is accomplished in a conventional manner, the now rigid and non-deformable assembly is. placedon the surface to be imprinted. The frame 1 is constructed so that on all sides thereof the frame extends below the screen 2. This extension automatically determines the necessary spacing gap between the screen and the surface to be imprinted. the scraper 3 is now moved in a conventional manner from one end of the screen to the other.

In a known way, a system comprising an arm 13 hinged from axle 4, a roller 14 mounted in a flange which oscillates with respect to the arm 13, and a guide rail 15 of the roller equipped with convenient ramps and stops permits one to obtain automatically, on the one hand, the proper pressure of the scraper upon the screen or, on the other hand, the lifting of the scraper,

depending upon the direction of the force applied to the latter.

To make a print on a cylindrical object (not shown), the frame 1 is fastened in a conventional manner to the movable portion of the support structure when the support structure is in-its closed position (FIG. 1). The printing head is brought into operative association with the object holder 23, previously described and shown in FIG. 3. Telescopic arm 1 l is then put in place to connectcross bar 6 and carriage 10. When the object is placed on the idle rollers, the printing head then being in the retracted position, a pulling traction exerted on the front crossbar 9 moves the movable portion of the support structure and the screen fastened thereto forward and the scraper carrying carriage l0, pushed by its spring means, follows to total deployment of the telescopic arm 11. The carriage is then immobilized in this position, which is adjustable due to the adjustment of stop 12, which should correspond perpendicularly to the upper generatrix of the cylindrical object. This position of the squeegee relative to the rigid frame member defines an operating position according to which the squeegee and the surface of the object to be printed are in operative alignment.

From this point on, by continuing the pulling motion on crossbar 9, one obtains simultaneously the passing of the screen between the scraper and the object and (hence) also the rotation'of the latter. At the end of the travel, the scraper is lifted, the screen is retracted by means of the telescopic slide and the scraper is pushed back against the telescopic-arm so as to disengage the object and enable its removal from its support.

FIG. 4 shows an alternate embodiment of the invention whichpermits use of screen frames of variable width. The constituent elements are similar to those of the printing head shown in FIGS. [-3 but the length of the transverse, or cross beams is variable; the rear cross bar 16 is telescopic, the front cross bar 19 is formed of two parts connected by a shaft 18 with opposing threads (turnbuckle), and both the axle 24 of the scraper and the cross member 25 of carriage 20 holding the scraper are adjustable in length, with portions 24a and 25a telescopically receiving therein portions 24b and 25b, respectively. In this embodiment, the scraper 3 is readily removable in a conventional manner by removing the head portion 3' from the axles 24 and 25. A different scraper is then provided which corresponds to the new adjusted width of the printing head. The means for fastening the head portion 3 to the axle 24 is conventional and need not be described further.

It is to be understood that the versions described and represented here are only given as non-limiting examples and can receive modifications and adjuncts without thereby going beyond the framework of the present invention. I

What is claimed is:

l. A silk screen printing assembly comprising in combination: a screen structureincluding a screen and a support frame for said screen; a support structure to which said support frame is mounted, said support structure including rigid frame member having parallel spaced legs joined by a transverse leg, and parallel spaced telescopic elements supported within said parallel spaced legs for telescopic movement relative thereto; a carriage; a squeegee; means mounting said squeegee to said carriage, and means mounting said carriage to said support structure for relative movement with respect to said support structure, wherein the telescopic movement permits the mounting of screen structures of varying length to said support structure, and wherein a stencil is applied to a surface positioned beneath the printing assembly by the relative displacement of said squeegee and said telescopic elements.

2. A silk screen printing assembly as claimed in claim 1, wherein said support structure further includes a cross bar which extends transversely of and joins together said telescopic elements, and wherein said transverse leg and said cross bar include laterally adjustable means for laterally adjusting the parallelism of said parallel spaced legs and said parallel spaced telescopic elements.

3. A silk screen printing assembly as claimed in claim 2, wherein the laterally adjustable means for the transverse leg is telescopic. 

1. A silk screen printing assembly comprising in combination: a screen structure including a screen and a support frame for said screen; a support structure to which said support frame is mounted, said support structure including rigid frame member having parallel spaced legs joined by a transverse leg, and parallel spaced telescopic elements supported within said parallel spaced legs for telescopic movement relative thereto; a carriage; a squeegee; means mounting said squeegee to said carriage, and means mounting said carriage to said support structure for relative movement with respect to said support structure, wherein the telescopic movement permits the mounting of screen structures of varying length to said support structure, and wherein a stencil is applied to a surface positioned beneath the printing assembly by the relative displacement of said squeegee and said telescopic elements.
 2. A silk screen printing assembly as claimed in claim 1, wherein said support structure further includes a cross bar which extends transversely of and joins together said telescopic elements, and wherein said transverse leg and said cross bar include laterally adjustable means for laterally adjusting the parallelism of said parallel spaced legs and said parallel spaced telescopic elements.
 3. A silk screen printing assembly as claimed in claim 2, wherein the laterally adjustable means for the transverse leg is telescopic. 